Characterization of Glis2, a Novel Gene Encoding a Gli-related, Krüppel-like Transcription Factor with Transactivation and Repressor Functions

Abstract

In this study, we describe the characterization of a gene encoding a novel Krü ppel-like protein, named Glis2. Glis2 encodes a relatively proline-rich, basic 55.8-kDa protein. Its five tandem Cys 2 -His 2 zinc finger motifs exhibit the highest homology to those of members of the Gli and Zic subfamilies of Krü ppel-like proteins. Confocal microscopic analysis demonstrated that Glis2 localizes to the nucleus. Analysis of the genomic structure of the Glis2 gene showed that it is composed of 6 exons separated by 5 introns spanning a genomic region of more than 7.5 kb. Fluorescence in situ hybridization mapped the mouse Glis2 gene to chromosome 16A3-B1. Northern blot analysis showed that the Glis2 gene encodes a 3.8-kb transcript that is most abundant in adult mouse kidney. By in situ hybridization, expression was localized to somites and neural tube, and during metanephric development predominantly to the ureteric bud, precursor of the collecting duct, and inductor of nephronic tubule formation. One-hybrid analysis using Glis2 deletion mutants identified a novel activation function (AF) at the N terminus. The activation of transcription through this AF domain was totally suppressed by two repressor functions just downstream from the AF. One of the repressor functions is contained within the first zinc finger motif. The level of transcriptional activation and repression varied with the cell line tested, which might be due to differences in cell typespecific expression of co-activators and co-repressors. Our results suggest that Glis2 behaves as a bifunctional transcriptional regulator. Both the activation and repressor functions may play an important role in the regulation of gene expression during embryonic development.

Teashirt 3 is necessary for ureteral smooth muscle differentiation downstream of SHH and BMP4

“…They derive from two cell populations, ectodermal epithelial buds and surrounding mesenchymal mesoderm, and unexpected parallels exist between MpTs development and vertebrate nephrogenesis (Denholm et al, 2003). Several fly MpT genes such as Kr, cut, hibris and Odd have vertebrate homologues (Glis2, Cux1, nephrin and Osr, respectively) implicated in kidney development (Sharma et al, 2004;Tena et al, 2007;Vanden Heuvel et al, 1996;Zhang et al, 2002). We have previously shown that stellate cells within MpT express two related zinc-finger transcription factors, teashirt (tsh) and tiptop (tio) (Denholm et al, 2003;Laugier et al, 2005).…”

Identification of Glis1, a Novel Gli-related, Krüppel-like Zinc Finger Protein Containing Transactivation and Repressor Functions

“…Expressions of Gli2 and -3, however, were reported in craniofacial structures and mesenchyme surrounding the vibrissal follicle. The expression pattern of Glis1 differs considerably to that of the recently described family member Glis2, which is found predominantly in neural tissues and somites (50,75).…”

“…Comparison of the amino acid sequence of Glis1 with those in the GenBank TM data base revealed that its ZFD exhibited high homology with those of the Krü ppel-like zinc finger proteins of the Gli and Zic subfamily (7,9,18,48,49), the recently described Glis2 (50), and with the ZFD of the Drosophila Gli-like zinc finger protein glf/Lmd (40,41) (Fig. 2).…”

“…domain in Glis1 appears to be novel and does not exhibit homology with the repressor domains recently identified in Glis2, a protein related to Glis1 (50). Repressor functions are often mediated through an interaction of the repressor domain with nuclear co-repressors.…”

Zic4, a zinc‐finger transcription factor, is expressed in the developing mouse nervous system

“…Zic genes are characterized by the presence of a zinc-finger domain (ZFD) that typically contains two cysteines and two histidines (C2-H2) that fold in a tetrahedral configuration around a central zinc ion (Pavletich and Pabo, 1993). Each Zic transcription factor contains five tandem repeats of the C2-H2 ZFD, which is highly homologous to the ZFD sequences of the Gli and Glis transcription factor families (Aruga et al, 1994(Aruga et al, , 1996aKim et al, 2002;Zhang et al, 2002).…”